1. Field of the Invention
The present invention relates to a method of obtaining and processing (managing) data obtained by a measurement or measurements (hereinafter referred to as “measurement data”) using a surface analysis instrument, such as an electron probe microanalyzer (EPMA), to which an energy dispersive X-ray spectrometer (EDS) is attached. The invention also relates to a measurement data structure adapted for this method. Furthermore, the invention relates to a method of reproducing a spectrum from measurement data having the above-described measurement data structure and to a surface analysis instrument using the measurement data structure.
2. Description of Related Art
Heretofore, a technique for detecting chemical elements present in a desired region on the surface of a sample using an energy dispersive X-ray spectrometer (EDS) has been known as disclosed in Japanese Patent Laid-Open No. S61-93938. In particular, the desired region is scanned in two dimensions with an electron beam by moving the beam relative to the sample. As the sample is scanned, X-rays are produced from the sample. The produced X-rays are spectrally analyzed by the EDS, and the number of photons present in each energy range is counted. Information about the obtained counts is processed to identify the elements present in the region.
The sample that undergoes X-ray spectral analysis using the EDS may be irradiated with a focused ion beam (FIB).
In energy dispersive X-ray spectroscopy (EDS), when the sample is being irradiated with an electron beam, the composition of the sample may vary with the elapse of time. That is, the electron beam irradiation itself may vary the composition. Furthermore, where the sample is heated or cooled, the composition may vary according to the heating time or cooling time. In addition, ion beam irradiation may vary the composition.
For example, where the sample is irradiated with an electron beam for 100 seconds, if it is to be examined how the concentration of a certain element contained in the sample varies, the concentration of a certain element in the sample is measured every 10 seconds, and the resulting data is stored. When the variation of the composition is examined every 10 seconds, the sample is irradiated with the electron beam for 10 seconds, and a spectrum is derived and stored. The sample is again irradiated with the beam for 10 seconds, and another spectrum is taken and stored. These process steps are carried out repeatedly. Since the operations for storing spectra are added, it cannot be said that the variation of the composition is examined on a real-time basis.
Where normal data is derived up to an intermediate point in a measurement, if the data is nullified during the measurement by contamination of the sample, the measurement must be redone from the beginning.
Where 10 measurements are performed every 10 seconds in this way, when the resulting file is being saved, the sample is being irradiated with the electron beam in practice. It has not been possible to measure the correct variation occurring during the irradiation of 100 seconds.
If the human analyzer recognizes that the time resolution of 10 seconds is too low, a new measurement must be performed at a different location provided that there is sample damage. That is, where the composition was attempted to be investigated every 10 seconds and then the human analyzer wants to perform measurements at a higher time resolution of 5 seconds rather than 10 seconds, the composition has varied during the process. Therefore, it is impossible to perform the same measurement at the same location. In this way, it has been impossible to derive data that would be identical with data obtained from 5 second-interval measurements after measurements were performed at intervals of 10 seconds in practice.
Furthermore, where a sample is irradiated with a focused ion beam for 100 seconds, there has been no means for investigating the relationship between the variation in the intensity of a certain chemical element contained in the sample and the process of creating the sample using the focused ion beam if it is desirable to utilize such means.
Any of the above-described conventional works has been cumbersome and laborious to perform.